I was reading a post in a watercolour group asking about when to stretch (ie tape) the paper for watercolours. So when do I tape? There are pretty much two factors, what paper and how wet I plan on painting. As far was what paper, if it is a small composition, and esp. thicker paper I can often get away without tape. For most small pet portraits, butterflies etc I don’t use tape. However for anything bigger (and really would 8 x 10 is starting to push your luck ) I would tape so the paper dried flat.
As far as how wet you get the paper, that matters for the 8 x 10 and smaller. For example, this new piece I obviously taped (see photo below), because I knew I was going to be applying the black in a heavy handed manner at the end. However I did a lotus flower and swallow tail butterfly awhile back, that is the same size and paper, but not use tape, because all the paint went on in small steps that that time to dry. In general though, if it crosses my mind, I think it is better to error on the side of using tape!
